1. Field of the Invention
The present invention relates to a dry flowable for plant disease control containing a polyoxin compound.
2. Related Art
Polyoxin compounds produced by Streptomyces cacaoi var. asoensis are nucleoside antibiotics, and they have been known to inhibit growth of pathogenic fungus of plant diseases such as rice sheath blight, pear Alternalia leaf spot, and rice brown spot. Therefore, agricultural chemicals containing the polyoxin compounds as an active ingredient in the form of emulsifiable concentrate and wettable powders have been marketed, and they have been used as fungicide for fruit orchards, tobacco, flowers, turfgrass and the like for the past 30 years or more.
However, the conventional emulsifiable concentrate containing the polyoxin compounds have a drawback that they are unstable as emulsions, and hence suffer from a short effective self-life. Therefore, their use may be limited, and aged emulsions must be discarded. In addition, activity of such conventional emulsifiable concent is not always stable depending on the kind of solvent used, diluted concentration and the like, and therefore they are not always convenient for use.
On the other hand, conventional wettable powders containing the polyoxin compounds also have drawbacks, for example, low content of active ingredient, dusty, unstable friability and dispersibility. Further, because they use clay minerals as a carrier, such clay minerals may adhere to plants to form noticeable taints.
As described above, the conventional formulations containing the polyoxin compounds have various kinds of problems, and there has been a need for developing a novel formulation which overcomes the problems mentioned above.
Meanwhile, environmental pollution due to excessive use of agricultural chemicals has recently become to be paid much attention as a social problem. That is, it is required to prevent as far as possible agricultural chemicals applied to plants or soil from flowing out to neighboring rivers with rainwater and the like to affect on fish occurring in the rivers, to contaminate source for water supply and the like. Therefore, it is desired to provide agricultural chemicals exhibiting excellent activity with a small amount. In particular, such chemicals are highly desirable for golf courses where total amount of agricultural chemicals to be used is limited by regulations.
Further, there are some diseases among those of turfgrass in golf courses and the like for which sufficient activity cannot be obtained unless a locally increased application amount of agricultural chemicals is used. Because the conventional wettable powders do not have sufficient friability, dispersibility and susupensibility, and they have a low content of active ingredients, a lot of water must be used for applying such formulations. Therefore, when such conventional wettable powders are used, greens in golf courses may be drowned and this may make it difficult to play golf. Therefore, there is also a need for developing a formulation requiring less water for application.
An object of the present invention is to solve these problems observed in the prior art. That is, the object of the present invention is to provide a dry flowable containing a polyoxin compound having good friability, dispersibility and suspensibility when mixed with water. Another object of the present invention is to provide a dry flowable capable of efficiently bring out the activity of polyoxin compounds as agricultural chemicals, having a high content of active ingredient, and requiring less amount of water for application.